Fraunhofer Institute for Production Technology IPTResearchproject "EnablingSapphire"
Challenges of sapphire processing
Sapphire is more than just a gemstone: as a high-performance material, it combines extreme hardness, chemical resistance, and optical transparency – from UV to infrared. Whether in quantum technology, high-frequency electronics, or medical technology, sapphire enables applications that would be unthinkable with conventional materials.
However, processing it is a challenge. Until now, only simple geometries could be feasible. More complex 3D structures are costly to produce and often suffer from quality issues such as microcracks, surface roughness, or form deviations.
The EnablingSapphire research project aims to address these challenges.
Hybrid manufacturing chain for producing complex components from sapphire
As part of the research project, Fraunhofer IPT and Fraunhofer ILT are developing a digital manufacturing platform for producing complex sapphire components and tools from industrially available semi-finished sapphire products. To achieve this, the researchers integrate laser-based shaping and polishing processes with advanced forming technologies such as precision glass molding.
Laser-based shaping and polishing
The project investigates the shaping of complex 3D geometries using ultrashort laser pulses. The aim is to produce structures with undercuts, minimum radii of less than 100 µm, and aspect ratios of more than 10:1. At the same time, process parameters such as beam shaping and thermal pretreatment are optimized to minimize stresses and microcracks.
Another focus is on laser-based polishing to achieve low-stress, crack-free surfaces up to optical quality. In addition, processes for surface functionalization are being developed, including Glassy Carbon coatings with and without microstructures, such as refractive or diffractive structures, and metallization for conductor tracks. The microstructures will be manufactured using Two-photon-polymerization combined with a pyrolysis process to achieve different free form shapes for the coating..
High-temperature forming using sapphire tools
Sapphire pressing tools are being investigated for the high-temperature forming of demanding glasses such as borosilicate and quartz glass, with process temperatures exceeding 1400 °C. In this temperature range, conventional tool materials reach their limits due to wear and dimensional instability. In addition, targeted surface functionalization, such as glassy carbon coatings, is applied to reduce adhesion, thereby improving demoldability and extending tool lifetime.
Application and validation
The developed process chain is validated using three demonstrators:
- Ion traps for quantum technologies
- Sapphire tools for high-temperature forming of borosilicate and quartz glass optics
- Through-wafer vias for high-performance and high-frequency electronics
These applications demonstrate the platform's potential for a wide range of key technologies.
Funding
The “EnablingSapphire – Digital manufacturing platform for producing complex sapphire components” project is funded by the Fraunhofer internal program PREPARE.
Project partners
- Fraunhofer Institute for Laser Technology ILT (coordination)
- Fraunhofer Institute for Production Technology IPT